<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8" />
		<title></title>
	</head>
	<body>
		<script type="text/javascript">
			// var a = (); //error
			var b = []; //长度为0的数组
			var c = {}; //自定义对象
			
			var fun = function(){
				d=1;
			}
			fun();
			console.log(d)
		</script>
	</body>
</html>
